Liquid fertilizer metering pump



April 1960 D. JOHNSTON LIQUID FERTILIZER METERING PUMP Filed May 3, 1957 3 Sheets-Sheet 1 INVENTOR DOUGLAS JOHNSTON ATTORNEY April 1960 DJJOHNSTON LIQUID FERTILIZER METERING PUMP 3 Sheets-Sheet 2 Filed May 5, 1957 INVENTOR DOUGLAS JOHNSTON /MM @M ff ATTORNEY April 19, 1960 JOHNSTON 2,933,049

LIQUID FERTILIZER METERING PUMP Filed May 3, 1957 S Sheets-Sheet 3 FIG. 4

lllllllil INVENTOR DOUGLAS JOHNSTON i, MW QMWW 4 ATTORNEY LIQUID FERTILIZER METERING PUMP Douglas Johnston, Huntsville, Ala., assignor to John Blue Company, Huntsville, Ala., a corporation of Alabama Application May 3, 1957, Serial No. 656,821

4 Claims. (Cl. 103-175) The present invention relates to reciprocating piston pumps, and more particularly to a pump of the type which is provided with a double-acting piston so that the pumping action occurs throughout a full 360 of the stroke, regardless of the pumps setting. Further, the pump is of the type especially adapted for farm use in distribution of liquid fertilizer, such as a nitrogen solution.

Pumps of this general nature are known, but such pumps have been found unsatisfactory in the pumping of liquid fertilizer such as nitrogen solutions in that the liquid fertilizer corrodes the working parts of the pumps at a rather rapid rate. Because such prior pumps are not easily serviceable, it is rather costly to replace worn or corroded parts.

Accordingly, it is an object of the present invention to provide a reciprocating piston-type pump that is compact, efficient, and easily serviceable.

Another object of the present invention is to provide a pump with wearing parts made'of stainless steel or other corrosive resistant materials, the wearing parts being easily accessible for servicing or replacement.

A still further object of the present invention is to provide a pump having a double-acting piston, which will accurately meter a liquid fertilizer despite gas formations in the fertilizer solutions.

Still another object of the present invention is to provide a pump of the type described in which the intake and discharge valves are so arranged as to be readily removable from the pump for replacement or repair, the valves also being arranged so as to provide full unobstructed flow through the valve seats, thereby minimizing formation of gas and pressure drops in using liquid fertilizer.

A further object of the present invention is to provide' a piston-type pump wherein the packing for the piston is mounted exteriorly of the piston in the cylinder block assembly. Ancillary to the preceding object, it is a further object of the present invention to provide a cylinder block assembly which may be easily disassembled so that the packing for the piston or the piston itself may be readily removed and replaced.

Still another object of the present invention is to provide a pump of the type described which accurately meters a liquid fertilizer solution, the metering being controlled by adjusting the stroke of the piston, and the adjusting means being simpler, more accurate and easier to lock in a fixed desired position.

Still another object of the present invention is to provide a reciprocating piston pump wherein spaced packing glands for the piston rod afford means to protect certain wearing parts of the pump from contact with a liquid solution capable of corroding the parts.

A further object of the present invention is to provide a reciprocating piston pump wherein the crankcase for housing the crankshaft and connecting rod for the piston rod is protected by spaced packings cooperating with the piston rod and wherein means are provided to nited States Ptent Figure 3 is a sectional view, taken on the line 3-3 of Figure 2.

Figure 4 is a side elevational view of the crankcase for the pump assembly, taken on the line 4-4 of Figure 5, the cylinder block of the pump assembly being removed for purposes of clarity.

Figure 5 is a sectional view taken on the line 5-5 of Figure l, the crankshaft being rotated from that shown in Figure '1.

Referring now to the drawings, wherein like characters or reference numerals represent like or similar parts,

there is illustrated a pump assembly having a doubleacting piston which is effective for pumping action throughout a full 360 of its stroke, regardless of the pump setting. The pump assembly comprises essentially a crankcase 9, a stutfing box assembly 11 detachably secured to the crankcase, a cylinder block assembly 10 forming a cylinder 12, and a piston assembly 28 adapted for reciprocation in the cylinder 12. The pump assembly is adapted to be supported on a farm implement, such as a tractor or the like, and is driven from one of'the ground wheels of the tractor or other vehicle. A suitable sprocket and chain drive driven by the ground wheel is adapted to drive, through a clutch, a sprocket mounted on a crankshaft 13. This drive train, from the'ground wheel to the crank shaft 13, is not illustrated, but it may be similar to that shown in Patent No. 2,696,785, granted December 14, 1954. The crankshaft 13 extends into the crankcase 9 of the pump assembly. The suction or intake side of the pump assembly is connected to a supply tank for liquid fertilizer below the bottom of the tank and the discharge side of the pump is connected through suitable conduits to a distributor head or the like carried on the tractor and capable of distributing the liquid fertilizer.

section of ground.

In more detail, the cylinder block assembly 10 is formed of two sections 14 and 16, the sections 14 and 16 having peripheral abutting flanges 18 and 20 respectively which are detachably secured together by nut and bolt assemblies 22, as best shown in Figure 2. A suitable gasket 15 is interposed between the abutting peripheral flanges 18 and 20. As best shown in Figure 1, section l6 of the cylinder block assembly 10 is provided with a closed end 24 which acts as a cylinder head for one end of the cylinder 12. Section 14 is open at its end opposite the closed end 24 of section 16 but when the stuffing box assembly 11 is detachably secured to the cylinder block assembly, the stuffing box will act as a cylinder head for the other end of cylinder 12. A more detailed description of the attachment of the stuffing box assembly 11 to the cylinder block assembly 10 will ap pear later in the specification.

Since the piston assembly 28 is of the double-acting type so that the cylinder 12 is provided with two compression chambers, the lower portion of the cylinder block assembly is provided with suction passageways 34 and 36 adjacent each of its ends which communicate with Patented Apr. 19,

By operation of the clutch, the crankshaft can be rotated so as to operate the pump and cause distribution of liquid fertilizer to a particular the eylinder 1 2. A suction valve chest 46 having a manifold 48, is detachably secured to the cylinder block assembly by means of machine bolts 49, as best shown in Figure 3. The suction manifold 43 is connected by suitable. conduits to a supply tank for the liquid fertilizer. Valve chest 46 is made of two sections 51 and 53, the sections being coupled together by a tubular hose or gasket 55 and a hose clamp 57. The section 51 supports a suction valve 50 cooperating with suction passageway 34, whereas the section 53 supports a second suction. valve 52 cooperating with suction passageway 36. The suction valves 50 and 52 are substantially identical in structure and the desoription of the suction valve 50 will suffice for the suction valve 52., A

eb. 5.2 Pro ides. n a b ss 61 c t s t n. 51 suppo af'valve stem 63 of the valve 50. Mounted on the lgpuer; nd if. he tem .3 s, a valv s r n s at lem .5 A coil compression spring 67 encircling valve stem 63 and u snzate l e w en h 1 ement .5 and w b 59-. 1.1;:- only urea e a e nt c in ugss uen h a va ve. sea 6.5! supp rted in a ou r 1 r de in the section 16 adjacent the suction passageway 34. When the piston assembly 28 is moving to the left of Figure l the suction, caused by such movement will raise'the valve 50 off of the seat 69 so that there will be substantially unobstructed flow of liquid from the manifold 48 through the passageway 34 into the right hand end of cylinder 12. As mentioned above, valve 52 is constructed substantially identical to valve 50 and operates in exactly the same manner when the piston assembly 28 is moving toward the right of Figure l.

A discharge valve chest 38. detachably secured to the cylinder block assembly by means of machine screws or bolts 73, as best shown in Figure 2, houses discharge valves 42 and 44 which cooperate respectively with discharge passageways. 30 and 32 provided in the sections 6. we e ec v of e cylinder, b a k ass m l al -e hss 81 o id d i h a dis ha e manit ld, whieh is adapted to. be connected by suitable conduits to thedistributor head or the like. The discharge passageways 30 and 32 communicate with the cylinder 12 adjacent its ends and. are positioned substantially opposite to the suction passages 34 and 36 respectively. Since the discharge valves 42 and 4.4 are substantially identical in construction, the description of the valve 42 will suf fice for the valve 44.

As is, best shown in Figures 1 and; 2, the valve chest i v made of w c s 5,-. and ple e h y. a, ub lar b s r. a ke nd. a in amp A boss 83 of; the sectioh 75. is provided with, a web 85 hi h n ma ve tem8 o e a yesz. A c compress on spring, 89, encircling valve stem 87 and interposed between thl web 85 and thevalve 42 urges the valve into seating engagement with a valve seat 91 supported in a counterbore 93 provided in the passageway 30, When the piston assembly 28' moves toward the right of Figure 1 the. discharge valve 44 will be closed and the liquid in the right hand end of cylinder 12 will be forced out through the valve 42 which opens against the springte nsion of coil spring 89. When the valve 42 is open it provides an unobstructed flow for the liquid from; the discharge passageway 30 to the manifold 40 where it is transferred through conduits to a suitable distributor head mounted on the tractor.

By providing the suction valves 50 and 52 on the bottom of the pump assembly, as shown in Figure 1, and by carrying the valves in a separate valve chest so that the valves, when opened, provide. a substantially unobstructed opening through the valve seat, the tendency for the formation of gas in the liquid fertilizer is minimized. Further, by providing the discharge or exhaust valves 42 and 44. on the topof the pump assembly and supporting these valves in a separate valve chest so that they do not substantialy obstruct the opening through the valye seat, reduces thepressure drop across the discharge valves and also allows any gas formation in the fertilizer solution to escape so that inaccuracy of metering is imized. The mounting of the suction and discharge valves in the valve chest, which may be easily'removed from the cylinder block assembly provides for easy serviceability of the valves and their valve seats should they need to be cleaned or replaced.

As is best shown in Figure l the piston assembly 28 includes a piston head 95 and a tubular piston plunger 97. The piston head 95 fits into a counterbore 99 in the tubular piston plunger 97 and is retained in position by a lock ring 101. An O-ring seal 193, provided about the periphery of the piston head 95, provides a seal between the periphery of the piston head 95 and the counterbore 99 of the tubular piston plunger 97. The piston assembly 2 8 is secured to the end of apiston rod by means of a lock nut 107. Sections 14 and 16 of cylinder block assembly 10 are provided with counterbores 109, L- shaped section, adjacent their peripheral abutting flanges 18 and 20. Flange packings 111, L-shaped in cross-section and separated by a flange packing washer 113, are carried in the counterbores 109 and cooperate with the outside wall of the tubular plunger 97 of piston assembly 28. By supporting the packings 111 in the cylinder block assembly 10, the walls of the cylinder 12 do not have to be machined and polished to provide a leakproof fit as. it is only necessary to polish the outside wall of the tubular piston plunger 97. Since the pump assembly is used with liquid fertilizers that are corrosive in natureit is much more initially inexpensive to polish and smooth the outside of the piston plunger 97 rather than the walls of the cylinder 12. The use of stainless steel for the piston assembly prevents this part from corroding and consequently it is much easier to service the piston assembly and to replace the packings 111 rather than having to service the inside wall of the cyliner pck s embly By s pp t g the p i 111 t e. cy nder a k, ssemb y 1.0 djacent the abuttin an s t s nere y e essary to remove the t ass mblies 22 and separate the sections 14 and 16 to replace and service, the packings 111, as well as the piston assembl 28.

The stuffing box assembly 11 includes a first member 115 having a cylindrical extension 117 which is adapted to telescope within piston assembly 28, and a second member 119 which provides a crosshead slideway 121 for a crosshead 123 carried on the end of piston rod 105. The members. 119 and 115 are detachably secured to the cylinder block assembly 10 by means of the bolt and nut assemblies 125, as. best shown in Figures 2 and 3. Suitable, gaskets 127 are interposed between the abutting flanges of the members 115 and 119, as well as between the member 115' and the cylinder block assembly 10. The cylindrical extension 117 of the member 115 is providcd with a relatively deep counterbore 129 in which Chevron-type packing glands 130 are carried. The packing glands 130 are spring-urged into sealing engagement with thepiston rod 105 by means of a coil spring 131 interposed between a lock ring 133 and a washer 135 abutting against the end gland. By providing the lock ring and aspring of known tension, the packing glands can be urged into sealing engagement by propertension without thenecessity of requiring mechanical means, such as bolts. or screwed glands,for adjustment. An enlarged counterbore or'recess 137 provided in the member 115 opposite the counterbore 129 is adapted to telescopingly receive the end of; the member 119. Member 119 is provided with a counterbore 139 which carries Chevrontype packing glands 1 40 also spring-urged into sealing engagement with the piston rod 105 by means of a coil spring 141 interposed between a washer 143 and the end of thecounterbore or recess 137. Packing glands are longitudinally spaced from packing glands. 130 and since packing glands 130 receive full pressure of the liquid fertilizer solution being pumped, they will be the first of the packing glands to fail.

In order that a failure of packing glands 130 may be determined, a drain slot or groove 1 45 is provided in the end of member 119 and communicates with the counterbore 139 and a space 147 between the member 119 and the wall of the counterbore 137. A drain hole or bore 149, provided in the flanged end of member 115, permits any fluid leaking past the packing glands 130 and draining along the piston rod 105 to drain out of the pump assembly. When the operator sees the visual indication of liquid fertilizer coming out of a port 151 provided in a plug 153 carried in the end of drain hole 149, he will know that the front packing 130 is worn and that the stulfing box assembly should be disassembled and both packings 140 and 130 removed and replaced.

If desirable, a passageway 155, provided in the top portion of the flanged end of member 115 is adapted to communicate with the space 147 so that a drip type of oiler may be installed to drip oil onto the piston rod 105. If desired, rather than provide a drip type oiler, as is known to the art, the passageway 155 may be utilized to drip water onto the piston rod so as to dissolve any crystallized salts formed thereon by the liquid fertilizer.

As previously mentioned, the end of piston rod 105 opposite the piston head 95 is connected to the crosshead 12.3, which is adapted to slide or reciprocate in the crosshead slideway 121. The crankcase 9 is provided with an apertured side 157 through which a connecting rod 159 extends and is pivotally connected to the crosshead 123, as indicated at 161. The member 119 is provided with a flange 120 which is connected to the crankcase 9 by means of bolts or studs 163. A suitable gasket 165 is interposed between the flange 120 and the crankcase 9.

Crankcase 9 rotatably receives the crankshaft 13, which as previously mentioned, is driven through suitable clutch means by a chain and sprocket drive that is adapted to be operated by the ground wheel of the vehicle. A clutch-operating lever 167 is slidably mounted in a boss 169, provided on the top of the crankcase 9, the clutchoperating lever being adapted to be reciprocated through a mechanical linkage extending to the drivers seat.

As clearly shown in Figure 1 and Figure 5, the crankshaft 13 is rotatably mounted in inner and outer oiltight antifriction bearing assemblies 171 and 173 respectively carried by the crankcase 9. A spacer sleeve 175 snugly disposed in an extension 177 provided on the crankcase 9, separates the bearing assemblies 173 and 171 and a split-ring 179 locks the bearing assemblies from actual longitudinal movement along the crankshaft 13. An end 180 of the crankshaft 13 extends out an apertured cover plate 181 detachably secured to crankcase 9 by machine screws or studs 182. As shown in 'Figure 5, a pointer arm 183 is keyed to the crankshaft 13 by a key 185 held in place by a set screw 187. An eccentric 189 is keyed to the crankshaft 13 by a key 191, as shown in Figures 1 and 5. The eccentric 189 supports a second eccentric 193, which may be rotated thereon when it is desired to adjust the stroke of the piston assembly 28. The eccentric 193 rides in a ring 195 provided on the end of the connecting rod 159.

In order to adjust the relative position of eccentric 189 with respect to eccentric 193 so as to adjust the length of the stroke of piston assembly 28, eccentric 193 is provided with a hole 197 which is adapted to receive a pin 199 having a square head that slides in a slot in an arm 201 provided on a sleeve 203. The sleeve 203 extends out of the extension 181 of the crankcase 9 and an oil-tight antifriction bearing assembly 205 is interposed between the sleeve and the crankcase 9. Crankshaft 13 is pro- .vided with a circumferential groove 207 which is adapted to receive an O-ring 209 which provides a seal between the crankshaft and the sleeve. A ring element 211 having an arcuate slot 213 therein is keyed to the end of the sleeve member 203 by a key 215. A bolt 217 extending through the slot1213 or ring member 211'and through a hole 219 provided in the end of pointer arm 183 is provided with a nut 221 so that the ring member 211 and the pointer arm 183 may be detachably locked with respect to one another. An arcuate recess 223, provided in the ring member 211, is adapted to receive a scale 225 which indicates the metering setting of the pump.

When it is desired to adjust the length of the stroke of piston 28, it is merely necessary to loosen the nut 221 from the bolt 217 so that the ring member may be rotated with respect to the pointer arm 183. Since the pointer arm 133 is keyed to the crankshaft 13, rotation of the ring member 211 will cause sleeve 20.3 to rotate and since sleeve'203 is pinned to the eccentric 193, the eecentric 193 will be rotated relative to-the eccentric 189. When the proper adjustment has been made the ring member 211 is locked to the pointer arm 183 and thus when the crankshaft 13 rotates the ring member will also rotate so that the eccentrics 189 and 193 rotate as a unit about the axis of rotation of the crankshaft 13. By means of this arrangement, it is clearly seen that the adjustment of the stroke is simpler, more accurate and easier to lock in position.

By the arrangement of parts in the pump assembly of the present invention, it is easily seen that the objects of the invention have been fully and eifectively accomplished. Since the cylinder block assembly 10 is made as a separate unit from the crankcase assembly it is not necessary to make the crankcase assembly of stainless steel, as the spaced packings and afi'ord protection to the crankcase assembly 9. The parts of the crankcase assembly 9 which are preferably made of stainless steel are the piston rod 105, washers 143 and 145, springs 131 and 141, snap rings 133 and 101, piston sleeve 97, as Well as the valve stems, valve springs, washers and nuts, in the valve chests 38 and 46. Each valve stem rides in a stainless steel bushing and the valve stems are chromium plated so that they will not seize with the bushings. Further, by making the cylinder block assembly 10 in separate sections 14 and 16, easy access may be had to the piston assembly 28 for service repair or for replacement. Utilizing the cylinder block assembly to hold the packing for the piston results in an inexpensive way to manufacture the pump assembly, as the tolerances of the tubular piston plunger 97 do not have to be as accurate as would the tolerance of the cylinder wall if the packings were mounted on the piston rather than in the cylinder wall. Further, the split cylinder block housing 10 affords an easy means of removing and replacing the packing 111 or the piston assembly 253. Utilizing suction and discharge valve chests 46 and 38 respectively for supporting the suction and discharge valves aflfords an easy means of servicing the valves. In addition, the valves are so constructed that they do not obstruct the suction and discharge passageways in the cylinder block assembly.

The terminology used in this specification is for the purpose of description and not limitation, the scope of the invention being defined in the claims.

I claim:

1. In a pump, the combination comprising: a cylinder block assembly having a cylinder therein provided with a closed end, an open end, and with a suction and a discharge passageway adjacent each of said ends; a doubleacting tubular piston reciprocal in said cylinder and having a closed end adjacent said cylinder closed end; a piston rod connected to said piston closed end and extending through said piston and through said cylinder open end; and a stulfing box assembly detachably secured to said cylinder block assembly and closing and extending into the open end of said cylinder in telescoping relation within said tubular piston, and in sealing relation with said piston rod, said assembly including gland means disposed substantially entirely within said cylinder.

2. The, structure defined in claim 1 in which the, piston is in sealing engagement with a portion of the cylinder intermediate the length thereof, the cylinder. is; interiorly enlarged adjacent both ends thereof, the suction and discharge passageways extend generally radially through said enlarged portions of said cylinder, and said passageways are overlapped by said piston during a portion of the stroke thereof.

3. The structure defined in claim 1 wherein the stuffing box assembly includes two sections each provided with a spring pressed packing gland and a drain passageway extending from between said glands to the exterior of said assembly.

4. The structure defined in claim 3 wherein they outer of the two sections, has an outer. extension defining. a cross head slideway.

Ref rence Cited in he fi at this natent UNITED STATES. PATENTS.

Caille Sept. 29, 1903 Petsche Nov. 14, 1911 Black Oct. 24; 1916 Myers July 19, 1921 Baum- Feb. 14, 1933 Sharp Aug. 13, 1935 Larson June 11, 1940 Maloney Ian. 13, 1-953 Hallden June 23, 1953 Lundh Mar. 2, 1954 FOREIGN PATENTS Great Britain --r t.- -.t Qf: 1. 8.1 

